JP5782345B2 - Method for producing laminated film - Google Patents

Description

  The present invention relates to a method for producing a laminated film (first laminated film) having a cured layer on one or both sides of a first transparent resin film having heat shrinkability. The first laminated film obtained by the production method is used to form a second laminated film by laminating a second transparent resin film having heat shrinkability on the cured layer via an adhesive layer. The second laminated film can be used for various applications such as optical applications.

  For example, when the second transparent resin film has a transparent conductive thin film, the second laminated film can be used as a laminate of the transparent conductive film. The transparent conductive film is used as a transparent electrode in a touch panel such as a display system such as a liquid crystal display or an electroluminescence display, an optical system, an ultrasonic system, a capacitance system, or a resistance film system. In addition, the transparent conductive film is used for antistatic and electromagnetic wave shielding of transparent articles, liquid crystal light control glass, transparent heaters and the like.

  Touch panels in which a transparent conductive film is used as an electrode include an optical method, an ultrasonic method, a capacitance method, a resistance film method, and the like depending on a position detection method. In a resistive touch panel, a transparent conductive film and a glass with a transparent conductor are opposed to each other via a spacer, and a current is passed through the transparent conductive film to measure the voltage in the glass with a transparent conductor. It has become.

  As the transparent conductive film, a pressure-sensitive adhesive layer is further provided on the conductive film provided with a transparent conductive thin film on one surface of the transparent film base so that it can withstand the scratch resistance and the hitting point characteristics during the pressing operation. Thus, a transparent conductive laminated film in which a transparent substrate having a hard coat layer on the outer surface layer is bonded to the other surface of the transparent film substrate has been proposed (Patent Document 1).

  When the transparent conductive film is incorporated in an electronic device such as a touch panel, a lead made of a silver paste is provided at the end of the transparent conductive film. The lead is formed by a method of heating and curing the conductive paste at about 100 to 150 ° C. for about 1 to 2 hours. However, since the heat-shrinkable transparent resin film such as polyethylene terephthalate is used for the transparent film substrate used for the transparent conductive film, there is a problem that curling occurs in the transparent conductive film by the heat curing treatment. . In particular, a transparent conductive laminated film in which a transparent substrate having a hard coat layer is bonded has a large problem with curling. In order to solve the curling problem, it has been proposed to make the hard coat layer thin or use a low shrinkage material for the transparent film base material. As a function cannot be satisfied.

  In addition, it has been proposed to use a transparent substrate having a hard coat layer on both sides for a transparent conductive laminated film (Patent Documents 2 and 3). However, curling of the transparent conductive laminated film can be suppressed by such a configuration, but in recent years, electronic devices such as touch panels have been made thinner, and the transparent conductive laminated film is also required to be thinned. The transparent conductive laminated film having the above configuration is not preferable from the viewpoint of thinning.

  Moreover, before providing a lead in a transparent conductive laminated film, it is possible to suppress the curling of a transparent conductive laminated film by heat-processing beforehand. However, subjecting the transparent conductive laminated film to further heat treatment increases the number of manufacturing steps, which is not preferable in terms of manufacturing cost.

  On the other hand, when a heat-shrinkable transparent resin film such as polyethylene terephthalate is used for the transparent film substrate used for the transparent conductive laminated film, a low molecular component (oligomer) contained in the transparent film substrate is used. ) Is precipitated by heating, and the transparent conductive film is whitened. For such a problem, it has been proposed to provide an oligomer prevention layer on a transparent film substrate.

Japanese Patent No. 2667686 JP 7-013695 A Japanese Patent Laid-Open No. 8-148036

  The present invention relates to a first transparent resin used for a second laminated film such as a transparent conductive laminated film (the first and second transparent resin films having heat shrinkability are laminated via an adhesive layer). A method for producing a first laminated film having a film and a cured layer, wherein curling can be suppressed even when a heat treatment step is applied to the second laminated film to which the first laminated film is applied, and It aims at providing the simple manufacturing method of the 1st laminated | multilayer film which can prevent precipitation.

  Another object of the present invention is to provide a method for producing a second laminated film from the first laminated film, which can suppress curling even when a heat treatment step is performed, and can prevent precipitation of oligomers. To do.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the object can be achieved by the following production method, and have completed the present invention.

That is, the present invention is a method for producing a first laminated film in which a cured layer is formed on one side or both sides of a first transparent resin film having heat shrinkability,
The first laminated film is used for forming a second laminated film by laminating a heat-shrinkable second transparent resin film on the cured layer of the first laminated film via an adhesive layer. And
The cured layer has a thickness of less than 1 μm;
Formation of the cured layer is as follows:
A composition solution containing an active energy ray-curable compound, a photopolymerization initiator (however, a 10% heat loss temperature in a heat loss test is 170 ° C. or higher) and a solvent are applied to one side or both sides of the first transparent resin film. Coating step (1) for coating to form a coating layer;
After the coating step (1), the solvent contained in the coating layer is dried so that the heat shrinkage rate when the obtained first laminated film is heated at 150 ° C. for 1 hour is 0.5% or less. Heat treatment step (2) performed under controlled temperature conditions;
It is related with the manufacturing method of the 1st laminated | multilayer film characterized by including the hardening process (3) which hardens a coating layer after the said heat processing process (2).

  In the method for producing the first laminated film, the photopolymerization initiator is 2-hydroxy-1- {4- [4- (2-hydroxy-methyl-propionyl) benzyl] phenyl} -2-methyl-propane-1. -One and / or 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one are preferred.

  In the manufacturing method of said 1st laminated | multilayer film, it is preferable that the usage-amount of the said photoinitiator is 0.1 weight part or more with respect to 100 weight part of active energy ray hardening-type compounds.

  In the manufacturing method of said 1st laminated | multilayer film, the temperature of heat processing process (2) can be set to 125-165 degreeC.

  In the manufacturing method of the first laminated film, the outermost layer on one side of the first laminated film may have a cured layer, and the outermost layer on the other side may have a functional layer. A hard coat layer is suitable as the functional layer.

Moreover, this invention, after obtaining the 1st laminated film by the said manufacturing method,
The manufacturing method of the 2nd laminated | multilayer film characterized by further including the lamination process (4) which bonds the 2nd transparent resin film which has heat shrinkability to the hardened layer of the said 1st laminated | multilayer film through an adhesive layer. , Regarding.

  In the method for producing the second laminated film, the second transparent resin film having a transparent conductive film directly or via an undercoat layer on the other side not bonded to the cured layer is used. it can.

  In the method for producing the second laminated film, in the case where the transparent conductive film is an amorphous transparent conductive thin film formed of a metal oxide, the amorphous transparent conductive film is formed after the lamination step (4). It may further include a crystallization step (5) for crystallizing the conductive thin film by heating.

  The first laminated film of the present invention has a first transparent resin film having heat shrinkability and a cured layer. The said hardened layer is formed from the composition solution containing an active energy ray hardening-type compound, a polymerization disclosure agent, and a solvent, and functions as an oligomer prevention layer. Therefore, also in the second laminated film obtained by laminating the second transparent resin film on the cured layer of the first laminated film via the pressure-sensitive adhesive layer, oligomer precipitation can be prevented.

  Moreover, the formation of the said hardened layer forms a coating layer by a coating process (1), Then, a predetermined heat treatment process (2) is given to the said coating layer. In the heat treatment step (2), the first transparent resin film is also heat-treated with drying of the solvent contained in the coating layer. The heat treatment is performed while controlling the temperature condition such that the heat shrinkage rate (both in the MD direction and the TD direction) is 0.5% or less when the obtained first laminated film is heated at 150 ° C. for 1 hour. It is. That is, since the first laminated film is obtained in a state where heat treatment has already been performed, even if the first laminated film is further subjected to heat treatment, thermal shrinkage hardly occurs and curling of the first laminated film is suppressed. be able to. Accordingly, curling can be suppressed even when the heat treatment step is applied to the second laminated film obtained by applying the first laminated film. In particular, the second transparent resin film used for the second laminated film is also controlled so as to have a heat shrinkage rate comparable to that of the first laminated film (preliminary heat treatment is applied to the first laminated film and the second transparent resin film. When the thermal shrinkage rate is controlled to be substantially the same), it is effective for preventing curling of the second laminated film. In the heat treatment step (2), the heat treatment of the first laminated film and the heat treatment of the first laminated film are performed simultaneously with the drying of the solvent, so that the heat treatment step conventionally performed after the production of the first laminated film or the second laminated film is omitted. The manufacturing method of the present invention is a low-cost and simple manufacturing method.

  The temperature condition of the heat treatment step (2) is such that the thermal shrinkage rate is 0.5% or less when the first laminated film is heated at 150 ° C. for 1 hour, so the solvent is simply dried. Temperature conditions severer than temperature conditions are set. On the other hand, since the temperature conditions of the heat treatment step (2) are severe, in the heat treatment step (2), the photopolymerization initiator present in the surface layer portion of the coating layer tends to volatilize. In the curing step (3) for curing the layer, the reactivity at the surface layer portion becomes insufficient, and the scratch resistance of the cured layer is deteriorated. In such a case, for example, when the first laminated film is transported to be bonded to the second transparent resin film, the cured layer of the first laminated film is scratched, resulting in poor appearance. Therefore, in the present invention, a photopolymerization initiator having a 10% heat loss temperature in a heat loss test of 170 ° C. or higher is used as the photopolymerization initiator in the composition solution used in the coating step (1). The photopolymerization initiator has extremely low volatilization from the surface layer portion of the coating layer, and even after the heat treatment step (2), the reactivity can be obtained in the curing step (3), and the scratch resistance is satisfied. A hardened layer can be formed. In addition, in order to supplement the volatile content of the photopolymerization initiator from the surface layer portion of the coating layer, it may be possible to use a large amount of photopolymerization initiator, but in the photopolymerization initiator other than the photopolymerization initiator of the present invention, In the heat treatment step (2), there is much volatilization from the surface layer portion of the coating layer, and it is difficult to form a cured layer that can satisfy the scratch resistance.

  Further, as described above, in the present invention, since a cured layer that can satisfy the scratch resistance can be formed, the thickness of the cured layer can be formed with a thickness of less than 1 μm. Thinning of the applied second laminated film can be achieved.

It is sectional drawing which shows an example of embodiment of the 1st laminated film of this invention. It is sectional drawing which shows an example of embodiment of the 2nd laminated | multilayer film of this invention. It is sectional drawing which shows an example of embodiment of the 2nd laminated | multilayer film of this invention. It is the schematic which shows an example of the manufacturing method of the 1st laminated film of this invention.

  Embodiments according to the first and second laminated films of the present invention and the manufacturing method thereof will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of the first laminated film 1 of the present invention. The first laminated film 1 in FIG. 1 is a case where a cured layer 11 is provided on one side of the first transparent resin film 10. The cured layer 11 can also be provided on both surfaces of the first transparent resin film 10. Moreover, in FIG. 1, the case where the functional layer (for example, hard-coat layer) 12 is provided in the single side | surface which does not have the hardened layer 11 of the 1st transparent resin film 10 is illustrated. In addition, when forming a functional layer in a 1st laminated | multilayer film, a functional layer is formed so that it may have a hardening layer in the outermost layer of one side of the 1st laminated film, and a functional layer in the outermost layer of the other single side | surface. . When the cured layer 11 is provided on both surfaces of the first transparent resin film 10, the functional layer 12 is formed on one cured layer 11.

  FIG. 2 is a cross-sectional view showing an example of the second laminated film 2 of the present invention. The first laminated film 2 (A) of FIG. 2A is a case where the second transparent resin film 20 is laminated on the cured layer 11 of the first laminated film 1 shown in FIG. The second laminated film 2 (B) of FIG. 2B is transparent conductive film 22 via the undercoat layer 21 on the other side of the second transparent resin film 20 not bonded to the cured layer 11 in FIG. 2A. The second laminated film 2 (B) in FIG. 2B can be used as a transparent conductive film. In FIG. 2B, the transparent conductive film 22 is provided via the undercoat layer 21. However, the transparent conductive film 22 is directly connected to the second transparent resin film 20 without using the undercoat layer 21. Can be provided.

  FIG. 3 is a schematic view showing an example of a method for producing the first laminated film of the present invention. The first laminated film 1 shown in FIG. 3 is a case where the cured layer 11 is formed on one side of the first transparent resin film 10. In FIG. 3, first, a coating layer 11 ′ is formed on one side of the first transparent resin film 10 by applying the composition solution in the coating step (1). Next, a coating layer 11 ″ obtained by drying the solvent contained in the coating layer 11 ′ is formed by the heat treatment step (2). The heat treatment step (2) is performed under temperature conditions such that the obtained first laminated film 1 satisfies a predetermined heat shrinkage rate of 0.5% or less. Next, the cured layer 11 is formed by curing the coating layer 11 ″ through the curing step (3). Although not shown in FIG. 3, by the lamination process (4), the second transparent resin film 20 (or the transparent conductive film 22 or the like on the second transparent resin film) is formed on the cured layer 11 of the first laminated film 1 obtained. The provided transparent conductive film) can be laminated via the pressure-sensitive adhesive layer 3 to produce the second laminated films 2 (A) and (B). In addition, in FIG. 3, although the process of forming the functional layer 12 is not described, the functional layer forming process may be performed on the first transparent resin film 10 before the coating process (1) is performed. You may give to the obtained 1st laminated film 1 or 2nd laminated film 2 (A), (B).

  Although not shown, in FIG. 3, when the second laminated film 2 (B) shown in FIG. 2B is manufactured, the transparent conductive film 22 of the second laminated film 2 (B) is subjected to metal oxidation. In the case of an amorphous transparent conductive thin film formed of a material, a crystallization step (5) for crystallizing the amorphous transparent conductive thin film by heating is further provided after the laminating step (4). be able to.

  First, the 1st laminated film 1 of this invention is demonstrated. The first laminated film 1 has a first transparent resin film 10 having heat shrinkability and a cured layer 11.

  As the first transparent resin film 10 having heat shrinkability, a plastic film that shrinks by heating at a temperature of about 150 ° C. for about 1 hour is used. For example, examples of the resin film having heat shrinkability include those that have been stretched in at least one direction. The stretching treatment is not particularly limited, and various stretching treatments such as uniaxial stretching, simultaneous biaxial stretching, and sequential biaxial stretching can be mentioned. The first transparent resin film 10 is preferably a biaxially stretched resin film from the viewpoint of mechanical strength.

  The material of the heat-shrinkable resin film is not particularly limited, and various plastic materials having transparency can be mentioned. For example, the materials include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins. , Polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyarylate resin, polyphenylene sulfide resin, and the like. Of these, polyester resins, polyimide resins and polyethersulfone resins are particularly preferable.

  Further, for example, as described in JP-A-2001-343529 (WO 10/37007), a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, and a substituted and / or unsubstituted phenyl and nitrile in the side chain And a resin composition containing a thermoplastic resin having a group. Specifically, a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer can be used as the material of the resin film.

  The first transparent resin film 10 is usually formed of a single layer film. In general, the thickness of the first transparent resin film 10 is preferably 30 to 250 μm, and more preferably 45 to 200 μm.

  The cured layer 11 is formed on one side or both sides of the first transparent resin film 10. The cured layer 11 has a function of preventing migration of a migration component in the first transparent resin film 10, for example, a low molecular weight oligomer component of polyester that is a migration component in the polyester film. The cured layer 11 is formed from a composition solution containing an active energy ray-curable compound, a photopolymerization initiator (however, a 10% heat loss temperature in a heat loss test is 170 ° C. or higher) and a solvent.

  Moreover, the thickness of the hardened layer 11 is less than 1 μm. In the heat treatment step (2), the photopolymerization initiator in the composition solution has little volatilization from the surface layer of the coating layer and can satisfy the scratch resistance even when the cured layer is thin. A prevention function can be added. Even if the thickness of the hardened layer 11 is 800 nm or less, or even 600 nm or less, the hardened layer can be provided with scratch resistance and an oligomer migration preventing function. In order to provide the cured layer 11 with sufficient scratch resistance and oligomer transfer function, the thickness of the cured layer 11 is preferably 120 nm or more.

  As the active energy ray-curable compound, a material having a functional group having at least one polymerizable double bond in the molecule and capable of forming a resin layer is used. Examples of the functional group having a polymerizable double bond include a vinyl group and a (meth) acryloyl group. The (meth) acryloyl group means an acryloyl group and / or a methacryloyl group, and (meth) in the present invention has the same meaning.

  Examples of the active energy ray-curable compound include an active energy ray-curable resin having a functional group having the polymerizable double bond. For example, oligomers or prepolymers such as acrylates and methacrylates of polyfunctional compounds such as silicone resins, polyester resins, polyether resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, polyhydric alcohols, etc. Etc. These may be used alone or in combination of two or more.

  In addition to the active energy ray-curable resin, a reactive diluent having a functional group having at least one polymerizable double bond in the molecule can be used as the active energy ray-curable compound. Examples of the reactive diluent include (meth) acrylate of ethylene oxide modified phenol, (meth) acrylate of propylene oxide modified phenol, (meth) acrylate of ethylene oxide modified nonylphenol, (meth) acrylate of propylene oxide modified nonylphenol, 2 -Ethylhexyl carbitol (meth) acrylate, isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (meth) ) Acrylate, diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, tripropylene glycol Monofunctional (meth) acrylates such as glycol monomethyl (meth) acrylate. Also, for example, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, polypropylene glycol di (Meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, di (meth) acrylate of ethylene oxide modified neopentyl glycol , Di (meth) acrylate of ethylene oxide modified bisphenol A, di (meth) acrylate of propylene oxide modified bisphenol A, ethylene oxide modified hydrogenated bis Enol A di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane allyl ether di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, Bifunctional (meth) acrylates such as propylene oxide-modified trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate; and further trifunctional The above (meth) acrylate is mentioned. Other examples include butanediol glycerin ether di (meth) acrylate and isocyanuric acid (meth) acrylate. A reactive diluent may be used individually by 1 type, and may use 2 or more types together.

  In addition to the active energy ray-curable compound, the composition solution for forming the cured layer can contain an inorganic material (inorganic oxide particles) in order to increase the hardness of the cured layer and suppress curling. Examples of the inorganic oxide particles include fine particles such as silicon oxide (silica), titanium oxide, aluminum oxide, zinc oxide, tin oxide, zirconium oxide, and mica. Among these, fine particles of silicon oxide (silica), titanium oxide, aluminum oxide, zinc oxide, tin oxide, and zirconium oxide are preferable. These may be used alone or in combination of two or more.

  The inorganic oxide particles are preferably so-called nanoparticles having a weight average particle diameter in the range of 1 nm to 200 nm. The weight average particle diameter is more preferably in the range of 1 nm to 100 nm. The weight average particle size of the inorganic oxide particles was measured by the Coulter counting method. Specifically, using a particle size distribution measuring device (trade name: Coulter Multisizer, manufactured by Beckman Coulter, Inc.) using the pore electrical resistance method, electrolysis corresponding to the volume of the particulates when the particulates pass through the pores. By measuring the electrical resistance of the liquid, the number and volume of fine particles were measured, and the weight average particle diameter was calculated.

  As the inorganic oxide particles, those bonded (surface modified) with an organic compound containing a polymerizable unsaturated group can be used. The polymerizable unsaturated group improves the hardness of the cured layer by reactive curing with the active energy ray-curable compound. As the polymerizable unsaturated group, for example, acryloyl group, methacryloyl group, vinyl group, propenyl group, butadienyl group, styryl group, ethynyl group, cinnamoyl group, maleate group, and acrylamide group are preferable. The organic compound containing a polymerizable unsaturated group is preferably a compound having a silanol group in the molecule or a compound that generates a silanol group by hydrolysis. It is also preferable that the organic compound containing a polymerizable unsaturated group has a photosensitive group.

  The inorganic oxide particles are preferably in the range of 100 to 200 parts by weight with respect to 100 parts by weight of the active energy ray-curable compound. When the blending amount is 100 parts by weight or more, the occurrence of curling and folding can be more effectively prevented, and when the blending amount is 200 parts by weight or less, scratch resistance and pencil hardness can be increased. . The blending amount is more preferably in the range of 100 to 150 parts by weight with respect to 100 parts by weight of the component (A).

  As the photopolymerization initiator, those having a 10% heat loss temperature of 170 ° C. or higher in the heat loss test are used. The photopolymerization initiator preferably has a 10% heat loss temperature in the heat loss test of 190 ° C. or higher. Regarding the physical properties of the photopolymerization initiator, it can be said that the heating loss (heating reduction rate) at a temperature increase of 170 ° C. in the heating loss test is preferably 10% or less. As for the said photoinitiator, it is more preferable that the heat loss at the temperature increase of 170 degreeC of a heat loss test is 5%, Furthermore, it is preferable that it is 2% or less.

  By using the photopolymerization disclosure agent, it is possible to prevent the photopolymerization initiator from volatilizing from the surface layer of the cured layer in the heat treatment step (2). As a result, the cured layer has sufficient reactivity in the curing step (3). And a sufficient function of preventing oligomer migration can be imparted to the cured layer. Examples of the photopolymerization initiator include 2-hydroxy-1- {4- [4- (2-hydroxy-methyl-propionyl) benzyl] phenyl} -2-methyl-propan-1-one, 2-methyl- 1- (4-methylthiophenyl) -2-morpholinopropan-1-one or the like can be used. In addition, the amount of the photopolymerization initiator used is 0.1 part by weight or more with respect to 100 parts by weight of the active energy ray-curable compound in order to obtain a sufficient degree of reactivity in the curing step (3). preferable. The amount of the photopolymerization initiator used is preferably 0.3 parts by weight or more, and more preferably 0.4 parts by weight or more. The amount of the photopolymerization initiator used is preferably 10 parts by weight or less, more preferably 7 parts by weight or less, from the viewpoint of hardness reduction.

  As the solvent used for the composition solution, a solvent capable of dissolving the active energy ray-curable compound or the like is selected. Specific examples of the solvent include ether systems such as dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrofuran; acetone , Methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, 2-octanone, 2-pentanone, 2-hexanone, 2-heptanone, 3-heptanone, etc. Ketone system; ester system such as ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, butyl acetate, n-pentyl acetate, methyl propionate, ethyl propionate; acetylacetone, diacetone alcohol Acetylacetones such as methyl acetoacetate and ethyl acetoacetate; methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-methyl-2-butanol, cyclohexanol, etc. Various solvents such as alcohols; glycol ethers such as ethylene glycol monoethyl ether acetate, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether, propylene glycol monomethyl ether acetate and propylene glycol monomethyl ether can be used. . These solvents can be used alone or in combination of two or more. The density | concentration of a composition solution is 1 to 60 weight% normally, Preferably it is 2 to 10 weight%.

  In forming the cured layer 11, first, a coating layer is formed by coating the composition solution on one or both sides of the first transparent resin film 10 in the coating step (1). As the coating method, a roll coating method such as reverse coating or gravure coating, a spin coating method, a screen coating method, a fountain coating method, a dipping method, or a spray method can be employed. The coating layer is formed so that the finally obtained cured layer 11 has a thickness of less than 1 μm.

  Next, the solvent contained in the coating layer is dried by the heat treatment step (2). Drying of the solvent is performed under control of temperature conditions such that the heat shrinkage rate when the obtained first laminated film 1 is heated at 150 ° C. for 1 hour is 0.5% or less. This heat treatment step (2) reduces the occurrence of curling in the obtained first laminated film 1 by preliminarily causing heat shrinkage to the obtained first laminated film 1 together with drying of the solvent. it can. The temperature of the heat treatment step (2) is appropriately set depending on the type of the first transparent resin film 10 and the type of the composition solution that forms the cured layer 11, and may be, for example, a temperature range of 125 to 165 ° C. preferable.

Next, in the curing step (3), the coating layer subjected to the heat treatment step (2) is cured. The curing means is usually performed by irradiating with ultraviolet rays. For ultraviolet irradiation, a high pressure mercury lamp, a low pressure mercury lamp, a halogen lamp, a xenon lamp, a metal halide lamp, or the like can be used. Arbitrary appropriate conditions can be employ | adopted as long as the irradiation conditions of an ultraviolet-ray are the conditions which can harden the said coating layer. The ultraviolet irradiation is preferably 50 to 500 mJ / cm ² in terms of the integrated light quantity at an ultraviolet wavelength of 365 nm. If irradiation amount is 50 mJ / cm < ² > or more, hardening will become more sufficient and the hardness of the hardened layer 11 formed will also become more sufficient. Moreover, if it is 500 mJ / cm < ² > or less, coloring of the formed hardened layer 11 can be prevented.

  Moreover, the 1st laminated film 1 can provide the functional layer (hard-coat layer) 12 as needed. As described above, the functional layer is provided so that the outermost layer on one side of the first transparent resin film 10 has the cured layer 11 and the outermost layer on the other side has the functional layer.

  As the functional layer 12 (excluding the cured layer), for example, a hard coat layer for the purpose of protecting the outer surface can be provided. As a material for forming the hard coat layer, for example, a cured film made of a curable resin such as a melamine resin, a urethane resin, an alkyd resin, an acrylic resin, or a silicone resin is preferably used. The thickness of the hard coat layer is preferably 0.1 to 30 μm. The thickness is preferably 0.1 μm or more for imparting hardness. On the other hand, if the thickness exceeds 30 μm, cracks may occur in the hard coat layer or curling may occur in the entire first laminated film 1.

  In addition, as the functional layer 12, an antiglare treatment layer or an antireflection layer for the purpose of improving visibility can be provided. An antiglare treatment layer or an antireflection layer can be provided on the hard coat layer. The constituent material of the antiglare layer is not particularly limited, and for example, an ionizing radiation curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used. The thickness of the antiglare treatment layer is preferably 0.1 to 30 μm. As the antireflection layer, titanium oxide, zirconium oxide, silicon oxide, magnesium fluoride, or the like is used. The antireflection layer can be provided with a plurality of layers.

  The second laminated film 2 of the present invention can be formed by laminating the second transparent resin film 20 having heat shrinkability on the cured layer 11 of the first laminated film 1 via the pressure-sensitive adhesive layer 3. it can.

  As the 2nd transparent resin film 20, the resin film which has the heat shrinkability similar to the said 1st transparent resin film 10 can be illustrated. The same material as the first transparent resin film 10 can be used for the second transparent resin film 20. Also about the 2nd transparent resin film 20, it can heat-process beforehand so that the thermal contraction rate of a 1st laminated | multilayer film and a 2nd transparent resin film may become substantially the same. The thickness of the second transparent resin film 20 is usually 10 to 300 μm, preferably 10 to 200 μm.

  The second transparent resin film 20 can be provided with the transparent conductive film 22 directly or via an undercoat layer on the other side not bonded to the cured layer 11.

  When the transparent conductive film 22 is provided on the second transparent resin film 20 to create a transparent conductive film, the thickness of the second transparent resin film 20 is preferably 10 to 40 μm, and preferably 20 to 30 μm. It is more preferable. If the thickness of the second transparent resin film 20 used for the transparent conductive film is less than 10 μm, the mechanical strength of the second transparent resin film 20 is insufficient. The operation of continuously forming the conductive film 22 may be difficult. On the other hand, if the thickness exceeds 40 μm, the input amount of the second transparent resin film 20 may be reduced in the film forming process of the transparent conductive film 22, and the gas or moisture removal process may be adversely affected, thereby impairing productivity. is there. Moreover, it becomes difficult to reduce the thickness of the transparent conductive laminated film.

  The second transparent resin film 10 is preliminarily subjected to etching treatment or undercoating treatment such as sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical conversion and oxidation on the surface, and a transparent conductive film provided thereon You may make it improve the adhesiveness with respect to said 2nd transparent resin film 20 of 22 or the undercoat layer 21. FIG. Further, before the transparent conductive film 22 or the undercoat layer 21 is provided, dust may be removed and cleaned by solvent cleaning or ultrasonic cleaning as necessary.

  The constituent material of the transparent conductive film 22 is not particularly limited, and for example, indium oxide containing tin oxide, tin oxide containing antimony, or the like is preferably used. When the transparent conductive film 22 is formed of the metal oxide, the transparent conductive film 22 is made amorphous by controlling the tin oxide in the material (containing a predetermined amount). can do. When forming an amorphous transparent conductive film, the metal oxide preferably contains 90 to 99% by weight of indium oxide and 1 to 10% by weight of tin oxide. Furthermore, it is preferable to contain 95 to 98% by weight of indium oxide and 2 to 5% by weight of tin oxide. In addition, after forming the transparent conductive film 22, it can crystallize by giving an annealing process within the range of 100-150 degreeC as needed.

  The amorphous transparent conductive thin film can be crystallized by performing a heat treatment as the crystallization step (5) after forming the second laminated film of the present invention. As the heating temperature in the crystallization step (5), the same temperature (100 to 150 ° C.) as the annealing treatment can be adopted.

  The term “amorphous” in the present invention refers to a polygonal shape on the entire surface of the transparent conductive thin film when the surface of the transparent conductive thin film is observed with a field emission transmission electron microscope (FE-TEM). Or the area ratio which an oval crystal occupies is 50% or less (preferably 0-30%).

The thickness of the transparent conductive film 22 is not particularly limited, but is preferably 10 nm or more in order to obtain a continuous film having a good conductivity of 1 × 10 ³ Ω / □ or less. When the film thickness becomes too thick, the transparency is lowered, and it is preferably 15 to 35 nm, more preferably in the range of 20 to 30 nm. When the thickness is less than 15 nm, the surface electrical resistance increases and it becomes difficult to form a continuous film. Moreover, when it exceeds 35 nm, transparency will fall.

  The method for forming the transparent conductive film 22 is not particularly limited, and a conventionally known method can be employed. Specifically, for example, a vacuum deposition method, a sputtering method, and an ion plating method can be exemplified. In addition, an appropriate method can be adopted depending on the required film thickness.

  The undercoat layer 21 can be formed of an inorganic material, an organic material, or a mixture of an inorganic material and an organic material. The undercoat layer 21 can be formed of a single layer or a plurality of layers of two or more layers. In the case of a plurality of layers, these layers can be combined.

For example, NaF (1.3), Na ₃ AlF ₆ (1.35), LiF (1.36), MgF ₂ (1.38), CaF ₂ (1.4), BaF ₂ (1. 3), inorganic substances such as SiO ₂ (1.46), LaF ₃ (1.55), CeF ₃ (1.63), Al ₂ O ₃ (1.63) Is the refractive index of Of these, SiO ₂ , MgF ₂ , A1 ₂ O _{3 and the} like are preferably used. In particular, SiO ₂ is suitable. In addition to the above, a composite oxide containing about 10 to 40 parts by weight of cerium oxide and about 0 to 20 parts by weight of tin oxide can be used with respect to 100 parts by weight of indium oxide.

The undercoat layer formed of an inorganic material can be formed as a dry process such as a vacuum deposition method, a sputtering method, or an ion plating method, or by a wet method (coating method). As the inorganic material forming the undercoat layer, SiO ₂ is preferable as described above. In the wet method, a SiO ₂ film can be formed by applying silica sol or the like.

  Examples of organic substances include acrylic resins, urethane resins, melamine resins, alkyd resins, siloxane polymers, and organic silane condensates. At least one of these organic substances is used. In particular, as the organic substance, it is desirable to use a thermosetting resin made of a mixture of a melamine resin, an alkyd resin, and an organosilane condensate.

  The thickness of the undercoat layer 21 is not particularly limited, but is usually about 1 to 300 nm, preferably 5 from the viewpoint of optical design and the effect of preventing oligomer generation from the second transparent resin film 20. ~ 300 nm. In addition, when providing two or more undercoat layers 21, the thickness of each layer is about 5-250 nm, Preferably it is 10-250 nm.

  The pressure-sensitive adhesive layer 3 can be used without particular limitation as long as it has transparency. Specifically, for example, acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate / vinyl chloride copolymers, modified polyolefins, epoxy systems, fluorine systems, natural rubbers, rubbers such as synthetic rubbers, etc. Those having the above polymer as a base polymer can be appropriately selected and used. In particular, an acrylic pressure-sensitive adhesive is preferably used from the viewpoint that it is excellent in optical transparency, exhibits adhesive properties such as appropriate wettability, cohesiveness and adhesiveness, and is excellent in weather resistance and heat resistance.

  Depending on the type of the pressure-sensitive adhesive that is a constituent material of the pressure-sensitive adhesive layer 3, there is one that can improve the anchoring force by using an appropriate pressure-sensitive adhesive primer. Accordingly, when such an adhesive is used, it is preferable to use an adhesive primer. The adhesive primer is usually provided on the second transparent resin film 20 side.

  The adhesive undercoat is not particularly limited as long as it is a layer that can improve the anchoring force of the adhesive. Specifically, for example, a silane coupling agent having a reactive functional group such as amino group, vinyl group, epoxy group, mercapto group, chloro group and hydrolyzable alkoxysilyl group in the same molecule, the same molecule Titanate coupling agent having hydrolyzable hydrophilic group and organic functional group containing titanium in the inside, and aluminum having hydrolyzable hydrophilic group and organic functional group containing aluminum in the same molecule A resin having an organic reactive group such as a so-called coupling agent such as an nate coupling agent, an epoxy resin, an isocyanate resin, a urethane resin, or an ester urethane resin can be used. From the viewpoint of easy industrial handling, a layer containing a silane coupling agent is particularly preferred.

  The pressure-sensitive adhesive layer 3 can contain a cross-linking agent corresponding to the base polymer. Further, the pressure-sensitive adhesive layer 3 may be made of, for example, natural or synthetic resins, glass fibers or glass beads, fillers made of metal powder or other inorganic powders, pigments, colorants, antioxidants, etc. These appropriate additives can also be blended. Moreover, it can also be set as the adhesive layer 3 which contained the transparent fine particle and was provided with the light diffusibility.

  The transparent fine particles include, for example, conductive inorganic fine particles such as silica, calcium oxide, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and antimony oxide having an average particle size of 0.5 to 20 μm. Alternatively, one or two or more suitable ones such as crosslinked or uncrosslinked organic fine particles made of a suitable polymer such as polymethyl methacrylate and polyurethane can be used.

  The pressure-sensitive adhesive layer 3 is usually formed from a pressure-sensitive adhesive solution (solid content concentration: about 10 to 50% by weight) in which a base polymer or a composition thereof is dissolved or dispersed in a solvent. As the solvent, an organic solvent such as toluene or ethyl acetate or an adhesive such as water can be appropriately selected and used.

  The method for forming the pressure-sensitive adhesive layer 3 is not particularly limited, and examples thereof include a method of applying a pressure-sensitive adhesive (solution) and drying, a method of transferring with a release film provided with a pressure-sensitive adhesive layer, and the like. As the coating method, a roll coating method such as reverse coating or gravure coating, a spin coating method, a screen coating method, a fountain coating method, a dipping method, or a spray method can be adopted.

  For bonding the cured layer 11 of the first transparent resin film 10 and the second transparent resin film 20, the pressure-sensitive adhesive layer 3 is provided on the second transparent resin film 20 side. The cured layer 11 side may be bonded, or conversely, the pressure-sensitive adhesive layer 3 is provided on the cured layer 11 side of the first laminated film 1, and the second transparent resin film 20 is bonded thereto. It may be.

The pressure-sensitive adhesive layer 3 is a second laminated film obtained after bonding the first laminated film and the second transparent resin film 20 (including the case of a transparent conductive film). It has a function of improving the scratch resistance of the transparent conductive film 22 provided on one surface of the resin film 20 and the hitting characteristics as a transparent conductive film for a touch panel, so-called pen input durability and surface pressure durability. From the viewpoint of better performing this function, it is desirable to set the elastic modulus of the pressure-sensitive adhesive layer 3 in the range of 1 to 100 N / cm ² and the thickness in the range of 1 μm or more, usually 5 to 100 μm. The said effect is fully exhibited as it is the said thickness, and the adhesive force of the 2nd transparent resin film 20 and the hardened layer 11 of the 1st laminated film 1 is also sufficient. If it is thinner than the above range, the durability and adhesion cannot be sufficiently secured, and if it is thicker than the above range, there is a possibility that a defect such as transparency may occur.

If the elastic modulus is less than 1 N / cm ² , the pressure-sensitive adhesive layer 3 becomes inelastic, and is easily deformed by pressurization and provided on the second transparent resin film 20 and further on the second transparent resin film 20. Unevenness is generated in the transparent conductive film 22 to be formed. In addition, the pressure-sensitive adhesive sticks out from the processed cut surface, and the effect of improving the scratch resistance of the transparent conductive film 22 and the impact characteristics of the transparent conductive film for touch panel is reduced. On the other hand, when the elastic modulus exceeds 100 N / cm ² , the pressure-sensitive adhesive layer 3 becomes hard, and the cushion effect cannot be expected. Therefore, scratch resistance of the transparent conductive film 22 and pen input as a transparent conductive film for a touch panel It tends to be difficult to improve durability and surface pressure durability.

  Moreover, since the cushion effect cannot be expected when the thickness of the pressure-sensitive adhesive layer 3 is less than 1 μm, the scratch resistance of the transparent conductive film 22 and pen input durability and surface pressure durability as a transparent conductive film for touch panel It tends to be difficult to improve. On the other hand, if it is too thick, the transparency is impaired, the adhesive layer 3 is formed, the workability of bonding the cured layer 11 of the first laminated film 1 and the second transparent resin film 20, and cost are also good. Hard to get.

  The second laminated film 2 (B) bonded through the pressure-sensitive adhesive layer 3 gives good mechanical strength, and in addition to pen input durability and surface pressure durability, in particular, curling and the like. This contributes to prevention of occurrence.

  The pressure-sensitive adhesive 3 can be protected with a release film until it is used for the bonding. As the release film, it is preferable to use a polyester film or the like in which a transition prevention layer and / or a release layer are laminated on the surface to be bonded to the pressure-sensitive adhesive layer 3.

  The total thickness of the release film is preferably 30 μm or more, and more preferably in the range of 60 to 100 μm. This is to suppress deformation (dentation) of the pressure-sensitive adhesive layer 3 that is assumed to be generated by foreign matter or the like that has entered between the rolls when the pressure-sensitive adhesive layer 3 is formed and stored in a roll state.

  The migration preventing layer can be formed of an appropriate material for preventing migration of a migration component in a polyester film, particularly a low molecular weight oligomer component of polyester. As a material for forming the migration prevention layer, an inorganic material, an organic material, or a composite material thereof can be used. The thickness of the migration preventing layer can be appropriately set within a range of 0.01 to 20 μm. The method for forming the migration preventing layer is not particularly limited, and for example, a coating method, a spray method, a spin coating method, an in-line coating method, or the like is used. Further, a vacuum deposition method, a sputtering method, an ion plating method, a spray pyrolysis method, a chemical plating method, an electroplating method, or the like can also be used.

  As the release layer, a layer made of an appropriate release agent such as silicone, long chain alkyl, fluorine, or molybdenum sulfide can be formed. The thickness of the release layer can be appropriately set from the viewpoint of the release effect. In general, from the viewpoint of handleability such as flexibility, the thickness is preferably 20 μm or less, more preferably in the range of 0.01 to 10 μm, and in the range of 0.1 to 5 μm. It is particularly preferred. The method for forming the release layer is not particularly limited, and a method similar to the method for forming the migration preventing layer can be employed.

  In the coating method, spray method, spin coating method, and in-line coating method, ionizing radiation curable resins such as acrylic resins, urethane resins, melamine resins, and epoxy resins, and the above resins include aluminum oxide and silicon dioxide. A mixture of mica and the like can be used. In addition, when using a vacuum deposition method, sputtering method, ion plating method, spray pyrolysis method, chemical plating method or electroplating method, gold, silver, platinum, palladium, copper, aluminum, nickel, chromium, titanium, iron, It is possible to use a metal oxide made of cobalt or tin, an alloy thereof, or another metal compound made of iodide steel.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to a following example, unless the summary is exceeded.

Example 1
(Formation of hard coat layer)
As a material for forming the hard coat layer, 100 parts by weight of acrylic / urethane resin (Unidic 17-806, manufactured by Dainippon Ink & Chemicals, Inc.), 1-hydroxy-cyclohexyl-phenylketone (Irgacure) as a photopolymerization initiator (184, manufactured by Ciba Specialty Chemicals) was added, and a toluene solution was prepared by diluting to a concentration of 30% by weight.

The material for forming the hard coat layer was applied to one surface of a 125 μm-thick polyethylene terephthalate film, which was the first transparent resin film, and dried at 90 ° C. for 3 minutes. Thereafter, ultraviolet irradiation was performed with a high-pressure mercury lamp at an integrated light quantity of 300 mJ / cm ² to form a hard coat layer having a thickness of 7 μm.

(Creation of first laminated film: formation of cured layer)
Cured layer forming material containing active energy ray-curable compound in which nano silica particles formed by bonding inorganic oxide particles and organic compound containing polymerizable unsaturated group are dispersed (trade name “OPSTAR” manufactured by JSR Corporation) Z7540 ”, solid content: 56% by weight, solvent: butyl acetate / methyl ethyl ketone (MEK) = 76/24 (weight ratio)). The hardened layer forming material includes dipentaerythritol and isophorone diisocyanate polyurethane as active energy ray curable compounds, silica fine particles whose surface is modified with organic molecules (weight average particle size of 100 nm or less), the former: the latter = 2: 3. In a weight ratio. 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (Irgacure) as a photopolymerization initiator per 100 parts by weight of the solid content of the active energy ray-curable compound of the cured layer forming material 907, manufactured by Ciba Specialty Chemicals, 10% heating weight loss temperature in heating loss test: 202 ° C.) 5 parts by weight were mixed. This mixture was diluted by adding butyl acetate and methyl ethyl ketone so that the solid content concentration was 10 wt% and butyl acetate / methyl ethyl ketone = 2/1 (weight ratio) to prepare a cured layer forming material.

The cured layer forming material was applied to the surface of the first transparent resin film opposite to the surface on which the hard coat layer was formed using a comma coater to form a coating layer. Subsequently, it heated at 145 degreeC for 1 minute, and the said coating layer was dried. Thereafter, ultraviolet irradiation was performed with an integrated light quantity of 300 mJ / cm ² with a high-pressure mercury lamp to form a cured layer having a thickness of 300 nm to obtain a first laminated film having a hard coat layer.

(Creation of transparent conductive film)
The temperature of the polyethylene terephthalate film is 100 ° C. in an atmosphere of 0.4 Pa composed of 80% argon gas and 20% oxygen gas on one surface of a 25 μm thick polyethylene terephthalate film as the second transparent resin film. Under the conditions, an ITO film having a thickness of 22 nm was formed by a reactive sputtering method using a sintered body material having a discharge power of 6.35 W / cm ² , 97% by weight of indium oxide and 3% by weight of tin oxide, A transparent conductive film was obtained. The ITO film was amorphous.

(Creation of second laminated film)
A pressure-sensitive adhesive layer is formed on the cured layer of the first laminated film, and a surface of the transparent conductive film on which the transparent conductive film is not formed is bonded to the pressure-sensitive adhesive layer to form a second laminated film. did. The pressure-sensitive adhesive layer formed a transparent acrylic pressure-sensitive adhesive layer having a thickness of 20 μm and an elastic modulus of 10 N / cm ² . The pressure-sensitive adhesive layer composition is obtained by blending 1 part by weight of an isocyanate-based crosslinking agent with 100 parts by weight of an acrylic copolymer having a weight ratio of butyl acrylate, acrylic acid, and vinyl acetate of 100: 2: 5. A thing was used.

  The obtained second laminated film was subjected to a heat treatment at 140 ° C. for 90 minutes to crystallize the amorphous ITO film.

Example 2
In the production of the first laminated film of Example 1 (formation of a cured layer), 2-hydroxy-1- {4- [4- (2-hydroxy-methyl-propionyl) benzyl] phenyl}-was used as a photopolymerization initiator. The second lamination was conducted in the same manner as in Example 1 except that 2-methyl-propan-1-one (Irgacure 127, manufactured by Ciba Specialty Chemicals, 10% heat loss temperature in heat loss test: 263 ° C.) was used. A film was obtained. Further, crystallization treatment was performed in the same manner as in Example 1.

Comparative Example 1
In preparation of the first laminated film of Example 1 (formation of a cured layer), 1-hydroxy-cyclohexyl-phenyl ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals, 10% heat loss in the heat loss test as a photopolymerization initiator) A second laminated film was obtained in the same manner as in Example 1 except that the temperature was 154 ° C. Further, crystallization treatment was performed in the same manner as in Example 1.

Reference example 1
In preparation of the first laminated film of Example 1 (formation of a cured layer), 1-hydroxy-cyclohexyl-phenyl ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals, 10% heat loss in the heat loss test as a photopolymerization initiator) Temperature: 154 ° C.), the drying temperature of the coating layer was changed to 80 ° C., and the heat treatment was further performed at 150 ° C. for 1 minute after ultraviolet irradiation. A second laminated film was obtained. Further, crystallization treatment was performed in the same manner as in Example 1.

  The following evaluation was performed about the 1st laminated film obtained by the Example and the comparative example, and the 2nd laminated film (transparent conductive laminated film) to which the crystallization process was performed. The results are shown in Table 1. In addition, in Table 1, it describes about the heat loss of the photoinitiator evaluated by the following method, and the thermal contraction rate (heating at 150 degreeC for 1 hour) of a 1st laminated film.

<Heating loss test>
The sample (photopolymerization initiator) was pretreated at 100 ° C. for 5 minutes before the test in order to remove volatile impurities such as water. Thereafter, about 10 mg of a sample (photopolymerization initiator) was heat-treated with a thermogravimetric analyzer (manufactured by Seiko Instruments Inc., Tg / DTA6200) at a rate of temperature increase of 5 ° C./min in a nitrogen stream. The temperature at which the calculated heat loss M (%) was 10% was measured. The heating loss M at a temperature increase of 170 ° C. was obtained by measuring the weight of the sample at 170 ° C. and calculating the heating loss M (%) at 170 ° C. from the following formula.
Weight of sample before heat treatment (M0), weight of sample after heat treatment (M1).
M (%) = {(M0−M1) / M0} × 100

<Heat shrinkage>
A first laminated film having a hard coat layer is cut into a 10 cm square, and the initial dimensions (initial dimensions) and the dimensions after heat treatment at 150 ° C. for 1 hour (post-heating dimensions) are measured. From the following formula, the thermal shrinkage rate in the MD direction and the TD direction was calculated.
Thermal contraction rate (%) = {(initial dimension−dimension after heating) / initial dimension} × 100

<Abrasion resistance of hardened layer surface>
A load of 250 g / 25 mmφ was applied to the steel wool and the hardened layer surface was reciprocated 10 times with a length of 10 cm, and then the state of the hardened layer surface was visually observed and evaluated according to the following criteria.
○: A thin scratch can be confirmed on the entire surface.
X: Remarkable scratches can be confirmed on the entire surface.

<Curl>
The second laminated film that has been crystallized is cut into a 10 cm square, placed on a horizontal plane with the curled surface facing down, and the longest point from the horizontal plane among the four corners. The distance (mm) was measured. The case where the recess is formed with the ITO formation surface facing up is marked as plus, and the case where the recess is formed with the hard coat layer formation surface facing up is marked as minus.

  As shown in Table 1, the first laminated film of the example has good scratch resistance of the cured layer, and no curl is observed even when the second laminated film is formed. On the other hand, in the cured layer of Comparative Example 1, since the photopolymerization initiator used for the forming material does not satisfy the heat reduction rate of the present invention, a high heat treatment temperature is applied to the thin coating layer. As a result, the scratch resistance is not satisfied. The cured layer of Reference Example 1 has good scratch resistance of the cured layer, and no curling is observed even when the second laminated film is formed. However, after the cured layer is formed, a heat treatment step is further performed. It is not advantageous in manufacturing.

DESCRIPTION OF SYMBOLS 1 1st laminated film 10 1st transparent resin film 11 Hardened layer 12 Functional layer (hard-coat layer)
2 Second laminated film 20 Second transparent resin film 21 Undercoat layer 22 Transparent conductive film 3 Adhesive layer

Claims (7)

After manufacturing the manufacturing method of the 1st laminated film which forms a hardened layer in the single side | surface or both surfaces of the 1st transparent resin film which has heat shrinkability, the 2nd transparent which has heat shrinkability in the hardened layer of the said 1st laminated film A method for producing a second laminated film comprising a laminating step (4) in which a resin film is bonded via an adhesive layer ,
The thickness of the cured layer in the first laminated film is less than 1 μm,
Formation of the cured layer is as follows:
A composition solution containing an active energy ray-curable compound, a photopolymerization initiator (however, a 10% heat loss temperature in a heat loss test is 170 ° C. or higher) and a solvent are applied to one side or both sides of the first transparent resin film. Coating step (1) for coating to form a coating layer;
After the coating step (1), the solvent contained in the coating layer is dried so that the heat shrinkage rate when the obtained first laminated film is heated at 150 ° C. for 1 hour is 0.5% or less. Heat treatment step (2) performed under controlled temperature conditions;
After the heat treatment step (2), viewed including the curing step (3) curing the coating layer,
The method for producing a second laminated film , wherein the second transparent resin film has a transparent conductive film directly or via an undercoat layer on the other side which is not bonded to the cured layer . The photoinitiator is 2-hydroxy-1- {4- [4- (2-hydroxy-methyl-propionyl) benzyl] phenyl} -2-methyl-propan-1-one and / or 2-methyl- The method for producing a second laminated film according to claim 1, which is 1- (4-methylthiophenyl) -2-morpholinopropan-1-one. The method for producing a second laminated film according to claim 1 or 2, wherein the amount of the photopolymerization initiator used is 0.1 parts by weight or more with respect to 100 parts by weight of the active energy ray-curable compound. . The temperature of a heat treatment process (2) is 125-165 degreeC, The manufacturing method of the 2nd laminated | multilayer film in any one of Claims 1-3 characterized by the above-mentioned. The method for producing a second laminated film according to any one of claims 1 to 4, wherein the outermost layer on one side of the first laminated film has a cured layer and the functional layer on the outermost layer on the other side. The method for producing a second laminated film according to claim 5, wherein the functional layer is a hard coat layer. The transparent conductive film is an amorphous transparent conductive thin film formed of a metal oxide, and after the laminating step (4), the amorphous transparent conductive thin film is crystallized by heating. (5) is further included, The manufacturing method of the 2nd laminated | multilayer film in any one of Claims 1-6 characterized by the above-mentioned.

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